Wall joint



Aug. 27, 1968 E. H. LARSON WALL JOINT Original Filed Oct. 15, 1965INVENTOR. ELTON H. LARSON AJ'TORNEYS United States Patent 3,398,494 WALLJOINT Elton H. Larson, 5105 Weeks, P.0. Box 10082, San Diego, Calif.92110 Continuation of application Ser. No. 496,643, Oct. 15, 1965. Thisapplication Jan. 3, 1967, Ser. No. 617,739 9 Claims, (Cl. 52-371)ABSTRACT OF THE DISCLOSURE Preformed joint for two wall sections of aroom, which wall sections are formed of plaster or stucco. The joint isinthe form of a unit including two coextensive screeds, one beingattachable to one of the wall sections and the other being attachable tothe other wall section. A coextensive strip is formed of impervious andinherently expansibleand contractible material which is interposedbetween flat sections of the aforementioned screeds, and is permanentlybonded throughout both sides thereof with the fiat sections of thescreeds.

The present application is a continuation of my application Ser. No.496,643, filed Oct. 15, 1965, now 'abandoned, which application is acontinuation-in-part of my application Ser. No. 218,383, filed Aug. 21,1962, now abandoned.

Walls formed of plaster or stucco contract due to curing thereof, andalso after curing, expand and contract due to changes in temperature.Such contractions and expansions cause cracking at the joints betweentwo wall sections, with the result that patching must be done from timeto time. Prior attempts have been made to overcome this need forpatching, but such attempts were unsuccessful. One attempt now beingused by the industry is as shown in the patent to Clark, No. 3,015,194,granted Jan. 2, 1962 on an application filed in June 1955. In actualpractice, the plaster breaks away from the pleats 20 and 21, shown inthat patent, while the plaster is curing. Furthermore, the resilientfold is formed of metal which, due to expansion and contraction,crystallizes and breaks. Moreover, it must be painted and when the paintis subjected to expansion or contraction, it cracks and falls away fromthe pleats. This pleat 10 is exposed to deteriorating atmosphereeffecting corrosion thereof.

In practicing the present invention, I employ a strip of polysulfidematerial or a material having a polyvinyl base or a polyvinyl chloride,the sides of which are bonded, i.e., welded respectively, with thescreeds.

Other features and the advantages of the present invention will beapparent from the following description, reference being had to theaccompanying drawing wherein preferred embodiments of the invention areillustrated.

In the drawing:

FIG. 1 is a fragmentary, cross-sectional view of one form of theinvention, showing the cross section of a fiat wall which may be avertical wall or a ceiling;

FIG. 2 is a top plan view of the wall shown in FIG. 1;

FIG. 3 is a fragmentary, cross-sectional view of the corner of joinedexterior walls; and

FIG. 4 is a fragmentary, cross-sectional view of the corner of interiorwalls.

Referring more in detail to the drawing and particularly to FIG. 1wherein there is shown fragments of a wall including two wall sections22 and 24; these wall sections are preferably formed of plaster orstucco. The sections 22 and 24 are aligned. The metal laths are shown at26 and 28 for the sections 22 and 24, respectively.

The joint comprises two screeds 30 and 32 in the form of elongatedstrips which are at least coextensive with the wall sections. In theembodiment shown in FIG. 1, the

3,398,494 Patented Aug. 27, 1968 screed 30 includes a relatively fiatsection 34, and a section 36 which latter is disposed at right angles tothe section 34. Like sections 38 and 40 comprise the strip 32. Thesections 34 and 38 of the strips 30 and 32 are disposed parallelly ofthe wall sections 22 and 24 and the sections 36 and 40 confront oneanother. The screed or strip sections 34, 36, 38 and 40 are providedwith a plurality of holes 42 through which the cementitious materialextends and when hardened, provide a mechanical joint between the wallsections 22 and 24 and the screeds. The extruded cementicious materialwhich extends through the openings 42 is shown at 44. The screeds arealso provided with angularly disposed strips 46 forming anchors whichextend into the cementicious material.

An impervious and inherently expansible and contractible finishing andjoining strip 50, which may have any desired color, is interposedbetween the confronting sections 36 and 40. The opposite sides of strip50 are bonded, i.e. Welded, to the confronting faces of sections 36 and40. The material forming strip 50, in one form, is polysulfide such asthat manufactured and sold by Chemical Corporation, 780 N. Clinton Ave.,Trenton 7, New Jersey, under the trade name of Thiokol. It may also beformed of material having a polychloride base or it may be a siliconesealant. In the embodiment shown in FIG. 3, the wall sections 22 and 24are at right angles with respect to one another, and, in thisembodiment, the sections 36 and 40 are disposed at a angle with respectto the respective sections 34 and 38.

In the embodiment shown in FIG. 4, the sections 36 and 40 of the screedsare formed at an acute angle of 45, respectively, with the sections 34and 38.

Thus, in FIG. 3 the contractible and expansible strip 50, which may becolored as desired, forms the finishing material for the corner of anoutside wall while in FIG. 4, the strip 50 forms the finishing materialfor the inside corner of the two walls.

The screeds 30 and 32 may be formed of galvanized metal or zinc and arepreferably formed by extruding a thermosetting polyvinyl chloride andthereafter the sealing strip is welded, i.e., bonded, to the confrontingsurfaces of the sections 36 and 40 of the screeds. The unit or assemblythus formed is sold in that form to the contractors. Thus, this unit isready to install on a construction project at a minimum, constructioncost compared to the very expensive system of installing two juxtaposedscreeds and thereafter, calking the sealing material between theconfronting surfaces of the screeds. The screeds and the strip 50 areherein shown at approximately full size.

It is well known that expansion and contraction take place in wallstructures after construction. An expansion of approximately one hundredpercent is more than ample for the material of strip 50 to take care ofall expansions and contractions between sections 22 and 24. It has beenfound that a polyvinyl chloride base expansible and contractiblematerial and silicone have the capacity of expanding more than onehundred percent, while it has been determined that polysulfide iscapable of expanding as much as five hundred percent.

From the foregoing, it is readily apparent that by virtue of the presentinvention, a simplified joint has been provided which is inexpensive tomanufacture as a unit and completely eliminates the necessity of calkingat the construction project. Thus, the cost of joining two sections ofwall has been materially reduced and provides for expediency inconstruction.

The strip 50 being bonded to the screeds 30 and 32 and being expandable,as aforementioned, cracks do not occur when the plaster cures, and,being compressible, the wall sections 22 and 24, carrying the screeds 30and 32,

3 can move toward one another when the wall sections expand. Too, theentire unit is formed of materials which cannot corrode. Furthermore,the material forming the strips 50 can be colored prior to being bondedto the screeds, and therefore, since the strips are inherentlyexpansible and contractible, they remain colored, as distinguished frompainted metal pleats which paint, when subjected to expansion orcontraction, cracks and falls away from the metal pleats.

While the forms of embodiment herein shown and described constitutepreferred forms, it is to be understood that other forms may be adoptedfalling within the scope of the claims that follow.

I claim:

. 1. An improved joint for two walls of a room, which walls are formedof material as for example, walls formed of plaster or stucco, whichimprovement comprises:

(A) a unit consisting only of:

( 1) a pair of elongated screeds, adapted for attachment, one to one ofthe walls and one to the other of the walls, each of said screedsincluding:

(a) an elongated, relatively flat section having holes for receiving Wetstucco;

(b) a second section disposed at an angle with respect to the flatsection and having holes for receiving wet stucco, said second mentionedsections of the screeds having faces confronting one another and spacedfrom one another;

(2) and an impervious and inherently expansible and contractiblefinishing and joining strip interposed between said second mentionedsections and permanently bonded throughout both sides thereof to bothconfronting faces of the second mentioned sections of the screeds.

2. An improved joint as defined in claim 1, characterized in that theexpansible and contractible strip is polysulfide.

3. An improved joint as defined inln ized in that the expansibleand.,contractibleastriphas3a 4 polychloride base.

4. An improved joint as defined in claim 1, characterized in that theexpansible and contractible strip is a silicone sealant. 4

5. An improved joint as defined in claim 1, characterized in that thescreeds are formed-of mate'rial having a polychloride base. a b

6. An improved joint as definedfi n clainigj'characterized in that thescreeds arl formed of mati'ial having a polychloride base.

7. An improved joint as defined in claim 3, characterized in that thescreeds are formed of material having a polychloride base.

8. An improved joint as defined in claim 4; characterized in that thescreeds are'formed of materia'fhavin'ga polychloride base. 1

9. An improved joint as defined in claim'5, character ized in that thescreeds are formedofmaterial havirfg a polychloride base.

References Cited FRANK L. ABBOTT, Primary Examiner. JAMES L. RIDGILL,IR., Assistant Examiner.

